For the purposes of the present invention atom interferometry refers generally to quantum mechanical interference processes that involve entities having a rest mass. Among other, such entities include atoms, ions and molecules. For a general overview of the quantum mechanical process of matter-wave interferometry the reader is referred to U.S. Pat. No. 3,761,721 to Altshuler and Franz. For a review of how matter-wave interferometry is applied in constructing inertial sensors the reader is further referred to U.S. Pat. Nos. 4,874,942 and 4,992,656 to John F. Clauser and the references cited therein.
Applications of atom interferometry in measuring kinematic properties of the various entities such as their velocities and accelerations have been explored in more detail by Chu et al. in U.S. Pat. Nos. 5,274,231 and 5,274,232. These references teach the use of the Raman process to induce internal energy transitions and thus affect the internal energy state of the entity as well as other kinematic properties such as its momentum or velocity. More precisely, pulses of electromagnetic energy are applied to the entity to stimulate transitions between non-radiative energy levels. The detuning of the electromagnetic pulses, i.e., the difference between the energy levels of the transition and the energy imparted by the electromagnetic pulses allows one to control the distribution of velocities among the entities. Precise control of the velocity distribution permits high accuracy measurements of properties such as velocities and accelerations. In turn, such precise measurements allow one to build more accurate kinematic sensors such as accelerometers and gyroscopes.
For practical inertial or kinematic navigation the kinematic properties, e.g., accelerations and rotation frequencies of the traveling object need not only be measured accurately but also frequently. In fact, for most navigation purposes the kinematic properties of the moving objects should be measured at time intervals on the order of 1 ms. Unfortunately, the best measurement accuracy in atom interferometers is obtained when measurements are performed over time intervals ranging from 10 ms to 500 ms since the accuracy of an atom interferometric measurement increases with measurement time. Hence, prior art atom interferometric sensors designed to serve as accelerometers or gyroscopes are not sufficiently quick for applications in precise kinematic navigation.